It’s often the case with technology that serious changes occur at a particular price or performance point in development. Something has small use until it can be developed to a certain combination of low price and high performance that everyone demands.
I believe that USB flash devices are going to be used for many interesting things starting about now. The reason is that 2G flash devices are now on sale for under $100. To be more precise 1G costs $45AU and
2G costs $85AU.
The above page on my web site has some background information on the performance of USB devices and the things that people are trying to do with them (including MS attempting to use them as cache).
One thing that has not been done much is to use USB for the main storage of a system. The OLPC machines have been designed to use only flash for storage as has the Familiar distribution for iPaQ PDAs (and probably several other Linux distributions of which I am not aware). But there are many other machines that could potentially use it. Firewall and router machines would work well. With 2G of storage you could even have a basic install of a workstation!
Some of the advantages of Flash for storage are that it uses small amounts of electricity, has no moving parts (can be dropped without damage), and has very low random access times. These are good things for firewalls and similar embedded devices.
An independent advantage of USB Flash is that it can be moved between machines with ease. Instead of moving a flash disk with your data files you can move a flash disk with your complete OS and applications!
The next thing I would like to do with USB devices is to install systems. Currently a CentOS or Red Hat Enterprise Linux install is just over 2G (I might be able to make a cut-down version that fits on a 2G flash device) and Fedora Core is over 3G. As Flash capacity goes up in powers of two I expect that soon the 4G flash devices will appear on the market and I will be able to do automated installs from Flash. This will be really convenient for my SE Linux hands-on training sessions as I like to have a quick way of re-installing a machine for when a student breaks it badly – I tell the students “play with things, experiment, break things now when no-one cares so that you can avoid breaking things at work”.
The final thing I would like to see is PCs shipped with the ability to boot from all manner of Flash devices (not just USB). I recently bought myself a new computer and it has a built-in capacity to read four different types of Flash modules for cameras etc. Unfortunately it was one of the few recent machines I’ve seen that won’t boot from USB Flash (the BIOS supported it but it didn’t work for unknown reasons). Hopefully the vendors will soon make machines that can boot from CF and other flash formats (the more format choices we have the better the prices will be).